Punitive anti theft on OBD plug

[Foscora]

Hey guys,

I recently helped a friend relocating his OBD plug to prevent it from stealing and he went like "hey why don't we wire some kind of punitive thing on this OBD, like reverting +/- and randomly add some +12/-12 in some of the other pins".

I liked the idea but it however went nowhere when we decided to give a try with an old chinese ODB cable. I was still able to plug the (undamaged) cable on an actual OBD plug without an issue.

Then it led me to an evil idea, I wired a 500V capacitor to the fake OBD plug, plugged in the cable (not plugged to a computer tho, I didn't want to try out) and ... after a punchy sparky sound, a nice "burnt-electronic-thingy smell" came to my nose from the cable

I'll have to work on something "safe for the car" (explosion wise) and think on a wiring that could keep this capacitor fully charged, but that could be a nasty "mod" (just gotta warn the potential shops the car goes to, in order to avoid "surprises" )

[PRY4SNO]

Seems like a lot of work for something very unlikely to happen.

If you're worried about theft why not pull the fuel pump fuse? Or have a hidden switch somewhere?

[elaw]

Okay I'm a bit of a dinosaur and am missing something here: what's the connection between the OBD plug and the car being stolen?

[Foscora]

Well on most moderns craps, you can start em with some kind of OBD hacking device which bypasses immobilzers (then u just have to screwdriver/start it or for card cars you can just plug a blank card and you're done).
On some most recent cars you can even do this (even opening doors) without anything but a phone+hacking device ...

The friend I've helped about this had his 2011 BMW stole like this, not a single sign of intrusion exception door handle dismantled ... A friend of him had the same issue with his RS4 B7.

Don't get me wrong it is not much of a trickery, just the way manufacturers shop do when you lose your keys, those devices are basically clones or whatever (I recall an old VW shopkeeper showing me a "VAG universal key" for all 197x-199x cars).

Anyways, the only way to start modern cars without keys/cards are the OBD slot, thats why some people relocate them.

Sure you can add some switches on fuel pump and so but I've witnessed this route before and modern ECUs and canbus are bad thing to mess with (it throw codes, won't start, asks for some manufacturer genuine car code, etc).

[90quattrocoupe]

So modern cars are a little tougher with the remote starting, doors that recognize the key, no exterior door locks, etc. But one place remains the same, the starter. It needs a signal wire to start the car. Relay the signal wire to the starter, connect kill switch to relay, find place for switch and no start.

On a modern manual car having the clutch switch, you can splice into it, relay and separate kill switch and the starter will not turn over. Most thieves these days won't even think about cars having kill switches.

Over the years, I have put a lot of kill switches in cars. Started with my 67 bug. #1 car stolen back in the 70's. Kill switch was on the lower seat rail. Simple on and off painted black. Looked like I was using the hand brake in the middle.

Greg W.